Method and apparatus for labeling of support structures

ABSTRACT

An apparatus for labeling support structures includes: a chassis having a locomotive assembly, and supporting an effector assembly with an end movable relative to the chassis and carrying a label modification unit with an image sensor; a controller coupled to the locomotive assembly, effector assembly and label modification unit, and configured to: obtain label modification data defining a location relative to a support structure reference feature for a label modification operation; control the locomotive assembly to travel to the support structure; detect the reference feature via image data captured at the image sensor; control the effector assembly to place the label modification unit at the location relative to the reference feature; control the effector assembly and the label modification unit perform the label modification operation.

BACKGROUND

Environments in which inventories of objects are managed, such asproducts for purchase in a retail environment, may be complex and fluid.A retail facility may contain a wide variety of products disposed onsupport structures such as shelves, which bear labels containing productinformation such as prices, barcodes and the like. The modification ofproducts within the facility, the selection of products on the shelves,and the formatting of the labels, may all change over time, requiringprevious labels to be replaced with new labels. The modification oflabels is typically performed manually, in a time-consuming anderror-prone process. Similar issues may be present in other environmentsin which inventoried objects are managed, such as in warehouseenvironments.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The accompanying figures, where like reference numerals refer toidentical or functionally similar elements throughout the separateviews, together with the detailed description below, are incorporated inand form part of the specification, and serve to further illustrateembodiments of concepts that include the claimed invention, and explainvarious principles and advantages of those embodiments.

FIG. 1 is a schematic of a mobile automation system.

FIG. 2A depicts a mobile automation apparatus in the system of FIG. 1.

FIG. 2B is a block diagram of certain internal components of the mobileautomation apparatus in the system of FIG. 1.

FIG. 3A is a side view of a label modification unit of the mobileautomation apparatus in the system of FIG. 1.

FIG. 3B is a side view of a label modification unit of the mobileautomation apparatus having a closed cover in the system of FIG. 1.

FIG. 4 is a flowchart of a method for labeling support structures.

FIG. 5 illustrates a support structure bearing labels for modificationthrough the method of FIG. 4.

FIGS. 6A and 6B depict detection of support structure reference featuresduring performance of the method of FIG. 4.

FIG. 6C illustrates example images captured during the detection processillustrated in FIGS. 6A and 6B.

FIG. 7 is a flowchart of a method for label modification.

FIGS. 8A-8C illustrate previous label detection at block 705 of themethod of FIG. 7.

FIG. 9A-9C illustrate previous label positioning at block 715 of themethod of FIG. 7.

FIGS. 10A-10C illustrate selective erasing and writing operations atblocks 720 and 730 of the method of FIG. 7.

Skilled artisans will appreciate that elements in the figures areillustrated for simplicity and clarity and have not necessarily beendrawn to scale. For example, the dimensions of some of the elements inthe figures may be exaggerated relative to other elements to help toimprove understanding of embodiments of the present invention.

The apparatus and method components have been represented whereappropriate by conventional symbols in the drawings, showing only thosespecific details that are pertinent to understanding the embodiments ofthe present invention so as not to obscure the disclosure with detailsthat will be readily apparent to those of ordinary skill in the arthaving the benefit of the description herein.

DETAILED DESCRIPTION

Examples disclosed herein are directed to an apparatus for labelingsupport structures. The apparatus includes a chassis having a locomotiveassembly; an effector assembly having a first end coupled to the chassisand a second end movable relative to the chassis; a label modificationunit at the second end of the effector assembly, the label modificationunit including an image sensor; and a controller coupled to thelocomotive assembly, the effector assembly and the label modificationunit. The controller is configured to obtain label modification datadefining a location relative to a reference feature on a supportstructure for a label modification operation; control the locomotiveassembly to travel to the support structure; detect the referencefeature via image data captured at the image sensor; control theeffector assembly to place the label modification unit at the locationrelative to the reference feature; and control the effector assembly andthe label modification unit to perform the label modification operation.

Additional examples disclosed herein are directed to a method forlabeling support structures, comprising: at a controller of anapparatus: obtaining label modification data defining a locationrelative to a reference feature on a support structure for a labelmodification operation; controlling a locomotive assembly of theapparatus to travel to the support structure; detecting the referencefeature in an image captured at an image sensor of the apparatus;controlling an effector assembly of the apparatus to place the labelmodification unit at the location relative to the reference feature; andcontrolling the label modification unit to perform the labelmodification operation.

FIG. 1 depicts a mobile automation system 100 in accordance with theteachings of this disclosure. The system 100 includes a server 101 incommunication with at least one mobile automation apparatus 103 (alsoreferred to herein simply as the apparatus 103) and at least one clientcomputing device 105 via communication links 107, illustrated in thepresent example as including wireless links. In the present example, thelinks 107 are provided by a wireless local area network (WLAN) deployedwithin the retail environment by one or more access points (not shown).In other examples, the server 101, the client device 105, or both, arelocated outside the retail environment, and the links 107 thereforeinclude wide-area networks such as the Internet, mobile networks, andthe like. The system 100 also includes a dock 108 for the apparatus 103in the present example. The dock 108 is in communication with the server101 via a link 109 that in the present example is a wired link. In otherexamples, however, the link 109 is a wireless link. As those of ordinaryskill in the art will realize, alternatively or in addition to theretail environment, embodiments of the present disclosure may beimplemented in a variety of environments in which inventoried objectsare managed, such as in a warehouse environment.

The client computing device 105 is illustrated in FIG. 1 as a mobilecomputing device, such as a tablet, smart phone or the like. In otherexamples, the client device 105 is implemented as another type ofcomputing device, such as a desktop computer, a laptop computer, anotherserver, a kiosk, a monitor, and the like. The system 100 can include aplurality of client devices 105 in communication with the server 101 viarespective links 107.

The system 100 is deployed, in the illustrated example, in a retailenvironment including a plurality of support structures in the form ofshelf modules 110-1, 110-2, 110-3 and so on (collectively referred to asshelf modules 110, and generically referred to as a shelf module110—this nomenclature is also employed for other elements discussedherein). Various other support structures for supporting inventoriedretail and/or warehouse items disposed thereon are contemplated,including shelves, racks (including racks for hanging inventoriedobjects, such as clothing racks), peg boards, and the like.

Each shelf module 110 supports a plurality of products 112. Each shelfmodule 110 includes a shelf back 116-1, 116-2, 116-3 and one or moresupport surfaces (e.g. an upper support surface 117 a-3 and a lowersupport surface 117 b-3 as illustrated in FIG. 1) extending from theshelf back 116 to a respective shelf edge (e.g. shelf edges 118 a-1, 118a-2, 118 a-3 and 118 b-3). The shelf modules 110 are typically arrangedin a plurality of aisles, each of which includes a plurality of modules110 aligned end-to-end. In such arrangements, the shelf edges 118 faceinto the aisles, through which customers in the retail environment aswell as the apparatus 103 may travel. The shelf edges 118 typically bearlabels corresponding to the products 112 and therefore includinginformation such as product names, barcodes or other machine-readableindicators, prices, and the like.

The labels can include adhesive labels affixed to the shelf edges 118,labels recorded or written on a rewriteable medium supported on theshelf edge 118 (e.g. by adhesives or the like), or other suitablelabels. In the discussion below, labels are recorded on rewriteablemedia supported on the shelf edges 118. In some examples, a piece (e.g.a strip) of rewriteable medium may extend across the shelf edge 118, ora portion thereof, and contain multiple labels corresponding torespective products 112. In other examples, the shelf edge 118 maysupport multiple rewriteable media in the form of discrete rewriteablelabels corresponding to respective products. In other words, the term“label” as employed herein can refer to either a discrete piece ofrewritable medium, or to a region of a strip of rewritable medium thatdefines several such regions (i.e. several labels). The rewriteablemedia may be for example a photothermal material having a first color,which, upon heating to a first threshold temperature, changes to andmaintains a second color (i.e. writing on the rewriteable medium), andupon heating to a second threshold temperature, reverts to and maintainsthe first color (i.e. erasing the rewriteable medium). For example, thesecond color can be black, grey or the like, while the first color canbe substantially white. More generally, the first color and the secondcolor contrast with one another.

As will be apparent from FIG. 1, the term “shelf edge” 118 as employedherein, which may also be referred to as the edge of a support surfaceof a support structure (e.g., the support surfaces 117) refers to asurface bounded by adjacent surfaces having different angles ofinclination. In the example illustrated in FIG. 1, the shelf edges 118a-3 is at an angle of about ninety degrees relative to each of thesupport surface 117 a-3 and the underside (not shown) of the supportsurface 117 a-3. In other examples, the angles between the shelf edges118 and the adjacent surfaces, such as the support surfaces 117, is moreor less than ninety degrees.

In the illustrated embodiment, the apparatus 103 is deployed within theretail environment, and communicates with the server 101 (e.g. via thelink 107) to navigate, autonomously or partially autonomously, along alength 119 of at least a portion of the shelf modules 110. The apparatus103 is configured to navigate among the shelf modules 110, for exampleaccording to a frame of reference 102 established within the retailenvironment. The frame of reference 102 can also be referred to as aglobal frame of reference. The apparatus 103 is configured, during suchnavigation, to track the location of the apparatus 103 relative to theframe of reference 102. In other words, the apparatus 103 is configuredto perform localization. The apparatus 103 is equipped with one or morenavigation sensors, including but not limited to image sensors, depthsensors, as well as gyroscopes and/or accelerometers, enabling theapparatus 103 to navigate within the environment.

The apparatus 103 also includes an effector assembly 104 bearing a labelmodification unit, to be discussed in greater detail below. Theapparatus 103 is configured, for example responsive to commands receivedfrom the server 101, to navigate among the shelf modules 110 and modifythe above-mentioned labels on the shelf edges 118 with the effectorassembly 104 and associated components. For example, certain labels mayrequire periodic modification to reflect updated prices, reallocation ofproducts 112 among the shelf modules 110, and the like. The server 101includes a memory storing a repository 120 containing label modificationdata, for example in the form of a planogram indicating the locations(e.g. in the frame of reference 102) of each shelf module 110, as wellas the location of each label on each shelf module. Label locations maybe expressed in the repository as a distance along a specified shelfedge 118 relative to a reference feature of the module 110, such as theboundary of the module 110 (e.g. the left side of the module 110). Thelabel modification data in the repository 120 can also contain furtherdata defining each label, such as the label type (i.e. the physicalformat of the label), the label content (e.g. as formatted sequencesindicating font size, font type, value, location, etc., or as a bitmap), the arrangement of the label content within the label, the productidentifier corresponding to the label, and the like.

Turning now to FIGS. 2A and 2B, the mobile automation apparatus 103 isshown in greater detail. Referring to FIG. 2A, the apparatus 103includes a chassis 200 containing a locomotive mechanism 204 (e.g. oneor more electrical motors driving wheels, tracks or the like). Thechassis 200 supports additional components of the apparatus 103,including a mast 208 which in turn supports the effector assembly 104.The effector assembly 104, in the present example, is a robotic armfixed to the chassis 200 (via the mast 208) at a first end 212. A secondend of the effector assembly 104 is movable relative to the chassis 200,for example with six degrees of freedom (e.g. translations in threedimensions, as well as roll, pitch and yaw angles). The second end ofthe effector assembly 104 carries a label modification unit 216. As willbe discussed in greater detail below, the label modification unit 216 isconfigured to perform label modification operations, such as erasing andwriting label content, as well as to capture data (e.g. image data) foruse in positioning the modification unit 216 via control of the effectorassembly 104.

The apparatus 103 also includes a hot air supply 228 configured tosupply hot air to the modification unit 216 for application to therewriteable medium to erase label content from the rewriteable medium.The hot air supply 228 can be implemented as a plurality of distinctcomponents. For example, the hot air supply 228 can be implemented asone or more pumps and associated storage tanks (e.g. air storage tanks)to supply air via an air conduit extending through a portion of the mast208 and the effector assembly 104 to the label modification unit 216, aswell as a heater (e.g. an inline heater within one or both of the mast208 and the effector assembly 104) mounted within the air conduit toheat the air. In other examples, additional label erasing mechanisms,such as a heated surface for application to the rewriteable medium, canbe deployed via the apparatus 103 in addition to or instead of the hotair supply 228, depending on the nature of the rewriteable medium.

The apparatus 103 also includes components for controlling andinteracting with the above components to modify labels on the shelfedges 118. Turning to FIG. 2B, the apparatus 103 includes aspecial-purpose controller, such as a processor 250 interconnected witha non-transitory computer readable storage medium, such as a memory 254.The memory 254 includes a combination of volatile memory (e.g. RandomAccess Memory or RAM) and non-volatile memory (e.g. read only memory orROM, Electrically Erasable Programmable Read Only Memory or EEPROM,flash memory). The processor 250 and the memory 254 each comprise one ormore integrated circuits.

The memory 254 stores computer readable instructions for execution bythe processor 250. In particular, the memory 254 stores a controlapplication 258 which, when executed by the processor 250, configuresthe processor 250 to perform various functions discussed below ingreater detail and related to the navigation of the apparatus 103 (e.g.by controlling the locomotive mechanism 204). The application 258 mayalso be implemented as a suite of distinct applications in otherexamples. The processor 250, when so configured by the execution of theapplication 258, may also be referred to as a controller 250. Thoseskilled in the art will appreciate that the functionality implemented bythe processor 250 via the execution of the application 258 may also beimplemented by one or more specially designed hardware and firmwarecomponents, such as field-configurable gate arrays (FPGAs),application-specific integrated circuits (ASICs) and the like in otherembodiments.

The memory 254 also stores a repository 260 containing, for example, amap of the environment in which the apparatus 103 is deployed, for usein navigation among the shelf modules 110. The apparatus 103 maycommunicate with the server 101, for example to receive instructions tonavigate to specified locations (e.g. to a given aisle consisting of aset of modules 110) and initiate label modification operations.Navigation to the specified module 110 is implemented by the apparatus103 based in part on the above-mentioned map. The repository 260 canalso contain label modification data (e.g. received from the server 101)for use in modifying labels on the shelf modules 110.

As shown in FIG. 2B, the processor 250 is connected to the effectorassembly 104, the locomotive mechanism 204, and the hot air supply 228.The processor 250 is enabled, via such connections, to issue commands tothe effector assembly 104 to control the position of the labelmodification unit 216 relative to the chassis 200, and to enable the hotair supply 228 to supply hot air for application at the modificationunit 216.

In addition, the apparatus 103 includes a laser 262, a steeringmechanism 264, and an image sensor 270 connected to the processor 250implemented as components of the modification unit 216.

The laser 262 is configured to emit a laser beam. The steering mechanism264 is configured to steer the laser beam directed at the rewriteablemedium for erasing and writing label content on the rewriteable medium.The steering mechanism 264 can be directly connected to the laser 262, asteerable mirror (e.g. configured to reflect the laser beam), or thelike. The laser 262 and the steering mechanism 264 are controllable bythe processor 250 to cooperate to emit a laser beam in a directiontowards the rewriteable medium to modify labels thereon. In particular,the laser 262 is controllable by the processor 250 to emit a laser beamat a first power level for heating the rewriteable medium to a firstthreshold temperature (e.g. about 180° C., although the first thresholdtemperature may be above or below 180° C. according to the particulartype or formulation of the rewritable medium) to write content on therewriteable medium and to emit a laser beam at a second power level forheating the rewriteable medium to a second threshold temperature (e.g.about 130° C. to about 170° C., although the second thresholdtemperature may be above 170° C. or below 130° C., according to theparticular type or formulation of the rewritable medium) to erasecontent on the rewriteable medium. In other examples, the processor 250may control the focus, shape or the like of the laser beam, for exampleto heat a larger area at a lower temperature for erasing, and to heat asmaller area at a higher temperature for writing. In some examples, thehot air supply 228 can be omitted, and the laser 262 can be used forboth writing and erasing, while in other examples, the laser can be usedonly for writing and the hot air supply 228 for erasing. In stillfurther examples, the laser 262 can be used for writing, and theapparatus 103 can select a removal mechanism from the laser 262 and thehot air supply 228 according to the erasing operation.

The image sensor can be for example a digital color camera (e.g.configured to generate RGB images), a greyscale camera, an infraredcamera, an ultraviolet camera or a combination of the above. The imagesensor 270 is controllable by the processor 250 to capture images of theshelf modules 110 in order to locate the modification unit 216 andmodify labels on the shelf edges 118.

The apparatus 103 can also include a cover 266 and a temperature sensor268 connected to the processor 250 and implemented as components of themodification unit 216.

The cover 266 is sized to fully block an opening of the modificationunit 216 to prevent a laser beam emitted by the laser 262 from leavingthe modification unit 216. The cover 266 is movable between a closedposition to fully block the opening and an open position to fully openthe opening. In particular, the cover 266 is controllable by theprocessor 250 for example via an electromagnetic, servo, or linear motoror the like to selectively block at least a portion of the opening todefine an operational portion of the opening through which the laser 262may emit a laser beam. When the cover 266 partially blocks the opening,laser beams emitted by the laser 262 are restricted to being directedthrough the operational portion of the opening; laser beams directed toother portions of the opening than the operational portion areobstructed from reaching the environment by the cover 266.

The temperature sensor 268 may for example be mounted within themodification unit 216 or within an air conduit running between the hotair supply 228 and the modification unit 216. The temperature sensor 268is configured to provide temperature measurements to the processor 250,and the processor 250 is configured to detect, based at least in part oncomparing the temperature measurements to a predetermined temperaturethreshold required to erase the label, whether a label has been erasedby the modification unit 216.

The apparatus 103 also includes a communications interface 274 enablingthe apparatus 103 to communicate with other computing devices, such asthe server 101 over the link 107 shown in FIG. 1. The communicationsinterface 274 also enables the apparatus 103 to communicate with theserver 101 via the dock 108 and the link 109.

Turning to FIG. 3A, the modification unit 216 is shown in greaterdetail. In particular, FIG. 3A illustrates a side view of themodification unit 216, when the modification unit 216 is oriented toerase or write content on a rewriteable medium on a shelf edge 118.

The modification unit 216 includes a housing 300 defining a cavity 304and an opening 308 at the front of the modification unit 216, the frontbeing the portion of the modification unit 216 configured to face and/orcontact the shelf edge 118.

The modification unit 216 also includes the cover 266. As shown in FIG.3A, the cover 266 is in a partially open position and partially blocksthe opening 308. The cover 266 defines an operational portion 312 of theopening 308, which is smaller than the opening 308. In the presentexample, the cover 266 extends from the bottom of the housing 300. Inother examples, the cover 266 may extend from the top or either side ofthe housing 300. In some examples, the modification may include multiplecovers 266 which cooperate to define horizontal and vertical dimensionsof the operational portion 312. The cover 266 is configured to bemovable from the closed position to the open position such that it doesnot interfere with positioning the modification unit 216 at or near theshelf edge 118. For example, as shown in FIG. 3A, the cover 266 isconfigured to move from the open position to the closed position withinthe cavity 304. In operation, the cover(s) 266 are configured to atleast partially block the opening 308, with the operational portion 312of the opening 308 being filled by the label being modified. Thecover(s) 266 therefore prevent the laser beam from inadvertentlyreaching areas of the environment other than the rewriteable medium. Themodification unit 216 can also include a biasing means, such as aspring, to bias the cover 266 to fully block the opening 308 (i.e.towards the closed position) when the cover 266 is not activelycontrolled by the processor 250. In the closed position shown in FIG.3B, the cover 266 fully blocks the opening 308 and prevents the laser262 from inadvertently reaching the environment, for example when theapparatus 103 is moving.

Also shown in FIG. 3A are the laser 262 and the steering mechanism 264disposed in the cavity 304. In the present example, the steeringmechanism 264 is a steerable mirror configured to reflect the laser beamemitted by the laser 262 towards the opening 308, and more particularly,through the operational portion 312.

FIG. 3A also depicts the image sensor 270 disposed in the cavity 304.The image sensor 270 is oriented to capture images depicting portions ofthe environment toward which the modification unit 216 is currentlyoriented (i.e. through the opening 308). More particularly, the imagesensor 270 captures images depicting portions of the environment visiblethrough the operational portion 312.

Also shown in FIG. 3A is an air conduit 316 connecting the hot airsupply 228 with the modification unit 216. The air conduit 316 is shownas being disposed on an exterior surface of the effector assembly 104,but in other embodiments can be disposed within the effector assembly104. The conduit 316 is configured to transmit hot air from the hot airsupply 228 to the modification unit 216 for use in modifying, andparticularly erasing, the rewriteable medium. The conduit 316 includesthe temperature sensor 268 mounted therein. The temperature sensor 268is configured to provide temperature measurements of the hot air to theprocessor 250 to determine whether the hot air has reached the requisitetemperature to heat and erase the label. For example, the requisitetemperature of the hot air may be about 170° C. to heat the label to thesecond threshold temperature of about 130° C. to about 170° C. forerasing the rewriteable medium.

In the present example, the air conduit 316 terminates in an outlet 320at or near the front of the modification unit 216. Hot air may beapplied to the rewriteable medium via the outlet 320. In other examples,the modification unit 216 can include structural features (e.g. a ventat the outlet, ridges on a front side of the cover 266 or themodification unit 216, a hollow cover 266 having venting apertures on afront side) configured to diffuse airflow of the hot air across therewriteable medium to increase efficiency of erasing. In furtherexamples, the hot air supply 228 may be integrated with the cover 266,for example by integrating a heating element with the cover 266 to heatthe air as it flows through or near the cover 266. For example, thecover 266 can include a heating wire, such as a nichrome wire, on afront side of the cover to heat the air as it flows through or near thecover 266.

FIG. 3B depicts a side view of the modification unit 216 including aheating wire 350 on a front side of the cover 266 in the closedposition. In operation, air is supplied from a generator (not shown) viathe conduit 316 to the outlet 320 and heated by the heating wire 350 forapplication to the rewriteable medium.

Also shown in FIG. 3A is an optical assembly 324 disposed in the cavity304 in the path of the laser beam. The optical assembly 324 iscontrollable by the processor 250 to change the shape of the laser beamaccording to the required erasing or writing operation.

The functionality of the apparatus 103, as implemented via execution ofthe application 258 by the processor 250 will now be described ingreater detail, with reference to FIG. 4. FIG. 4 illustrates a method400 of labeling support structures, which will be described inconjunction with its performance in the system 100, and in particular bythe apparatus 103, with reference to the components illustrated in FIGS.2A, 2B, 3A and 3B.

At block 405, the apparatus 103 is configured to obtain labelmodification data. The label modification data can be obtained from theserver 101 over the link 107 or via the dock 108. In other examples, thelabel modification data can be received from the client device 105. Thelabel modification data defines at least one location in the facilityfor performance of a label modification operation, such as modificationof a label to replace previous label content at the location with newlabel content, writing of a label in a previously unlabeled location, orerasure of a previous label, without placement of a new label. In thepresent example, the locations are locations on the shelf edges 118 ofthe shelf modules 110. Further, in the present example, the locationsare defined relative to a reference feature on the support structure.More specifically, each label modification location is defined as anoffset distance along a shelf edge 118 of a shelf module 110. The offsetdistance is defined from a side of the module 110 (e.g. the leftmostside of the module 110, also referred to as the boundary of the module110). In other examples, various other reference features can beemployed to define the locations in the label modification data, such asmachine-readable markers (e.g. physical features of the shelf, graphicalindicators such as QR codes, or the like) along the shelf edges, ends ofa shelf edge 118 within the boundaries of a module 110 (e.g. when ashelf edge 118 does not extend along the full length 119 of the module110), and the like.

Turning briefly to FIG. 5, a portion of an example shelf module 110having upper and lower shelf edges 118 a and 118 b, respectively, isshown. The shelf edge 118 a bears labels 500 and 504. The label 500 isat an offset 508 from a reference feature, in the form of a moduleboundary 516 (in the present example, the left side of the module 110),while the label 504 is at an offset 512 from the reference feature. Theoffsets 508 and 512, as well as indications of which shelf edge 118 thelabels 500 and 504 are affixed to, can be stored in the repository 120and obtained by the apparatus 103 at block 405, for storage in therepository 260. The label modification data obtained at block 405therefore contains, in the present example, an identifier of a shelfmodule 110, an identifier of a shelf edge 118 of the identified module110, and an offset distance along the identified shelf edge 118, from apredetermined reference feature of the identified module 110. The labelmodification data can also include label generation data, such as animage or other content for writing on rewriteable medium, or a productidentifier permitting the apparatus 103 to retrieve or generate suchlabel content. In some examples, the label modification data obtained atblock 405 can also include an indication of the previous label to bemodified (e.g. a product identifier or the like). Table 1, below,illustrates example label modification data obtained at block 405.

TABLE 1 Example Label Modification Data Module Shelf edge Offset (mm)Label Format Product ID 110 118a 150 1″ × 3″ 765554 110 118a 165 1″ × 3″778633 . . . . . . . . . . . .

As shown above, for each label to be modified, a location is provided(defined by the module and shelf edge identifiers, as well as theoffsets). Label generation data, in the example above, includes anidentification of a label format, which may specify both the size of thelabel as above, and the arrangement of information on the label (notshown above). The product identifiers are employed by the apparatus 103to retrieve information with which to populate the label format forgeneration of the label.

Returning to FIG. 4, at block 410 the apparatus 103 is configured tonavigate to the next support structure (e.g. the next module 110)identified in the label modification data. Navigation is performed via asuitable navigational mechanism, such as via the use of theabove-mentioned map, navigational sensors of the apparatus 103, and thelike. In the present example, the apparatus 103 is configured tonavigate to a predetermined location relative to the module 110. Forexample, modules 110 may have lengths of about 1.5 m (other modulelengths are also contemplated, for example from about 1 m to about 2 m),and the effector assembly 104 may have a reach of about 1 m.

Thus, the apparatus 103 is configured to navigate to a position at apredefined depth relative to the module 110, approximately half-wayalong the length 119 of the module 110, from which the effector assembly104 can reach any portion of the shelf edges 118 of the module 110. FIG.6A illustrates such a position, with the apparatus 103 having arrived ata depth 600 relative to the module 110, about half-way along the length119 of the module. As seen in FIG. 6A, the apparatus 103 is not exactlyhalf-way along the length 119. As will be apparent to those skilled inthe art, localization based on inertial sensing (e.g. via accelerometersand gyroscopes), as well as localization based on odometry (e.g. via awheel encoder coupled to the locomotive mechanism 204) may suffer fromnavigational errors, and the internal localization maintained by theapparatus 103 may therefore not align exactly with the true position ofthe apparatus 103 within the environment.

Returning to FIG. 4, at block 410 the apparatus 103 is also configuredto place the modification unit 216 at an initial location, from whichdetection of the above-mentioned reference feature will be initiated.Positioning of the modification unit 216 is achieved via control of theeffector assembly 104, for example by issuing commands from theprocessor 250 to the effector assembly 104 specifying coordinates (e.g.X, Y, Z coordinates and roll, pitch and yaw angles) that define aposition and orientation of the modification unit 216 relative to thechassis 200. The effector assembly 104 includes positional sensors (notshown) configured to track the position of the second end (i.e. themodification unit 216) of the effector assembly 104 relative to thefirst end 212, enabling the effector assembly 104 to position themodification unit 216 responsive to the above-mentioned commands fromthe processor 250.

The initial location is selected based on the known position (in theframe of reference 102) of the shelf edge 118 identified in the labelmodification data, as well as on the predetermined position to which theapparatus 103 navigated at block 410, and on a navigational errorboundary. For example, the navigational error mentioned above may havebeen previously characterized as reaching a maximum of about 0.1 m.Further, the height of the apparatus 103 and of the first end 212 of theeffector assembly 104 on the apparatus 103 are previously determined, asis the height of the shelf edge 118 a identified in the labelmodification data shown above. In the present example, the referencefeature is the boundary 516, and the apparatus 103 is thereforeconfigured to control the effector assembly 104 to place themodification unit 216 at an initial location at the height of the shelfedge 118 a, at a horizontal position adjacent to the boundary 516. As aresult of the potential for a positional error of up to 0.1 m, themodification unit 216 may be placed at a distance parallel to the length119 of about 0.85 m (half of the length 119 plus the maximum potentialnavigational error of 0.1 m).

At block 415 the apparatus 103 is configured to control the image sensor270 to capture an image. As shown in FIG. 6A, the modification unit 216is positioned to orient the image sensor 270 towards the module 110. Theimage captured at block 415 therefore depicts a portion of the shelfedge 118 a identified in the label modification data. At block 420 theapparatus 103 is configured to determine whether the reference featureis detected in the image captured at block 415. When the determinationis negative, the apparatus 103 is configured to repeat the performanceof blocks 415 and 420, incrementing the location of the modificationunit 216 along the shelf edge 118 a for each image capture. In otherwords, in the present example, in which the labels (i.e. the rewritablemedia bearing the labels) are affixed to substantially horizontal shelfedges 118, each incremental movement of the modification unit 216 atblock 415 maintains the modification unit 216 at a predetermined height(e.g. the height of the shelf edge 118 a as specified in the repository120, the repository 260, or the label modification data itself) andchanges the horizontal location by a predetermined increment to shiftthe field of view of the image sensor 270.

Referring to FIG. 6B, movement of the effector assembly 104 isillustrated, causing the modification unit 216 to traverse a portion ofthe shelf edge 118 from an initial position 604 (shown in FIG. 6A) to afurther position 608. FIG. 6C shows a sequence of three images 612, 616and 620 captured during the traverse shown in FIG. 6B. The determinationat block 420, in the present example, includes determining whether theimage captured at block 415 contains a substantially vertical gradientchange (e.g. from light, to dark, and back to light) indicative of a gapbetween modules 110 (which indicates the presence of the module boundary516). The determination includes the application of a suitable gradientdetection operation, edge detection operation or the like. In theexample images of FIG. 6C, the image 612 depicts a shelf edge of anadjacent module 110, and does not contain the boundary 516. The image616 contains a partial representation of the gap between modules 110,but does not contain the boundary 516 (e.g. does not contain thecomplete dark-light-dark transition mentioned above). The image 620,meanwhile, contains a dark-light-dark transition representing theboundary 516. Responsive to capturing the image 620, therefore, thedetermination at block 420 is affirmative and the performance of themethod 400 proceeds to block 425.

As will now be understood by those skilled in the art, the position ofthe image sensor 270 is fixed relative to the position of themodification unit 216. The image sensor 270 need not be centeredrelative to the opening 308 or the operational portion 312, but theposition of the image sensor 270 relative to the center of the opening308 or the operational portion 312 is nevertheless predetermined.Therefore, the location of a reference feature in an image captured bythe image sensor 270 indicates the position of the image sensor itself(and therefore the position of the modification unit 216) relative tothe reference feature.

At block 425, the apparatus 103 is configured to control the effectorassembly 104 to place the modification unit 216 at the next locationdefined in the label modification data. In other words, havingestablished the position of the modification unit 216 relative to thereference feature following an affirmative determination at block 420,the apparatus 103 is configured to move the effector assembly 104 toplace the modification unit 216 at the specified offset relative to thereference feature. Taking the label modification data of Table 1 as anexample, at block 425 the effector assembly 104 is controlled to placethe modification unit 150 mm to the right (in the orientation shown inFIGS. 5, 6A and 6B) of the boundary 516.

At block 430, the apparatus 103 is configured to modify a label at thelocation specified in the label modification data. The modification of alabel at block 430 will be discussed in greater detail in connectionwith FIG. 7. At block 435, the apparatus 103 is configured to determinewhether further labels remain to be modified on the current supportstructure (that is, the current module 110, to which the apparatus 103navigated at block 410). The determination at block 435 is made withreference to the label modification data obtained at block 405. If alllisted labels in the label modification data for the current module 110have been modified, the determination at block 435 is negative. When thedetermination at block 435 is negative, the apparatus 103 proceeds toblock 440. Otherwise, the apparatus 103 returns to block 425 to modifythe next label for the current support structure.

At block 440, the apparatus 103 is configured to determine whethersupport structures other than the current support structure areidentified in the label modification data and remain to be processed. Inthe example data shown in Table 1 above, only one module 110 isidentified. In other examples, however, the label modification data canidentify label modification locations on a plurality of distinct modules110. When the determination at block 440 is affirmative, the apparatus103 returns to block 410 to navigate to the next module 110 in the labelmodification data. As will now be apparent, during the performance ofblocks 415 to 435, the apparatus 103 is configured to remain stationaryrelative to the current module 110. That is, although the effectorassembly 104 and modification unit 216 move, the chassis 200 remainsstationary relative to the module 110, thus mitigating or eliminatingthe accumulation of further navigational errors during the labelmodification process.

Turning now to FIG. 7, the performance of block 430 will be discussed ingreater detail. FIG. 7 illustrates a method 700 of label modificationwhich will be described in conjunction with its performance in thesystem 100, and in particular by the apparatus 103, with reference tothe components illustrated in FIGS. 2A, 2B, and 3.

At block 705, having controlled the effector assembly 104 to place themodification unit 216 at the next label modification location at block425 as shown in FIG. 8A, the apparatus 103 is configured to detect thelabel at the label modification location. Detection of the label isachieved, in the present example, by controlling the image sensor 270 tocapture one or more images of the shelf edge 118 from the currentlocation of the modification unit 216 (i.e. the location specified inthe label modification data or modification of a label). Label detectioncan be performed via the detection of a barcode or other label featuressuch as strings of text in a captured image, the detection of one ormore edge features (e.g. indicated by gradient changes or the like), ora combination of the above. For example, the label modification data orother data in the repository 260 can contain indications of labelreference features and target positions for the label referencefeatures. The target positions may be defined, for example, relative tothe operational portion 312.

In some examples, the label reference features may be associated withthe label, such as label features written as content on the rewriteablemedium, or they may be associated with the rewriteable medium itself,such as a feature printed on or near an edge of the rewriteable medium,or a combination. In some examples, the label reference features may beprinted in ultraviolet (UV) ink. The image sensor 270, therefore, mayinclude a UV light source, and/or may have UV detection capabilities.

At block 705, the processor 250 can also be configured to select aremoval mechanism for the previous label 804. The selection can be basedon the label 804 and the label modification data. For example, theprocessor 250 may compare the previous label content with the new labelcontent obtained from the label modification data and determine adifference value representing a quantity of modification required, forexample as a function of laser erasing time, laser writing time, numberof pixels of a bit map, or the like. If the difference value is below athreshold value, the processor 250 may select the laser 262 for erasingat least a portion of the previous label content. Otherwise, theprocessor 250 may select the hot air for erasing the entire contents ofthe previous label 804. In other examples, the label modification dataor other data in the repository 260 can contain indications of suitableremoval mechanisms for each label format, or for particular productidentifiers. In other examples, such data is maintained in therepository 120, and the apparatus 103 transmits a request (e.g.containing the image 808 itself, or a product identifier decoded fromthe barcode on the label 804, or the like) for a removal mechanism tothe server 101.

At block 710, the processor 250 is configured to adjust the location ofthe modification unit 216 based on the label or the label referencefeatures detected at block 705.

For example, when a partial label is detected in an image captured atblock 705, the processor 250 is configured to increment the location ofthe modification unit 216, for example to center the modification unit216 over the partially detected label, or to position the detected labelreference features to their target positions, and to then capture afurther image via the image sensor 270 and repeat the detection. Theprocessor 250 may process the captured image(s) and adjust the locationof the modification unit 216 according to explicit predefined algorithms(e.g. if the label reference feature is too low, move the modificationunit 216), based on neural network approaches, or a combination.

For example, referring to FIG. 8B, an example image 800 captured via theimage sensor 270 is shown. The image 800 depicts a portion of the shelfedge 118 a, and depicts a portion of a previous label 804 recorded on arewriteable medium 806 supported on the shelf edge 118 a. The partialdetection of the previous label 804 may indicate that the previous label804 was not written on the rewriteable medium 806 at exactly thespecified location. The processor 250 can be configured to control theeffector assembly 104 to move the modification unit 216 along the shelfedge 118 a in the direction of the partially detected label 804 and tocapture a further image. A further image 808 is shown in FIG. 8C, inwhich the previous label 804 is fully visible. The processor 250, inother words, detects the previous label 804 as being coincident with thecurrent position of the modification unit 216 and therefore suitable formodification. The processor 250 can also be configured to compare thedetected label (e.g. a product identifier decoded from a barcode) toprevious label data included in the label modification data. When theprevious label 804 does not match the expected previous label, theprocessor can be configured to store an error message in the memory 254.

Referring to FIG. 9A, an example image 900 captured via the image sensor270 is shown. The image 900 depicts a portion of the label 804 visiblethrough the operational portion 312. The label 804 includes a labelreference feature 904-1 having a target position 908-1. The processor250 is configured to control the effector assembly 104 to move themodification unit 216 vertically and laterally to position the labelreference feature 904-1 at the target position 908-1. A further image912 is shown in FIG. 9B, in which the label reference features 904-1 and904-2 are at their respective target positions 908-1 and 908-2. Furtherlabel reference features 904-3 and 904-4 are also visible in theoperational portion 312.

The processor 250 can also extend the modification 216 towards the shelfedge 118. Extension of the modification unit 216 is performed to bringthe front of the modification unit 216 near or into contact with one orboth of the shelf edge 118 a and the rewriteable medium 806. Extensionof the modification unit 216 can also serve to effectively increase thesize of the label relative to the opening 308, and more particularly theoperational portion 312 of the modification unit. The processor 250 cancontrol the effector assembly 104 to extend the modification unit 216towards the shelf edge 118 a until, for example, the label referencefeatures are at their target positions. In other examples, the processor250 can control the effector assembly 104 to extend the modificationunit 216 towards the shelf edge 118 a until one or more sensors (e.g.strain gauges or the like) in the effector assembly 104 register athreshold resistance indicating that the modification unit 216 hascontacted the shelf edge 118 a.

Returning to FIG. 7, at block 715, the processor 250 is configured toadjust the size of the operational portion 312. For example, theprocessor 250 is configured to further detect the operational portion312. Detection of the operational portion 312 is achieved, in thepresent example, by controlling the image sensor 270 to capture one ormore images and process the captured image(s) to detect one or more edgefeatures (e.g. indicated by gradient changes or the like) of the housing300 and the cover(s) 266 defining the operational portion 312.

When the operational portion 312 is detected as being too large for thelabel, the processor 250 is configured to incrementally control thecover(s) 266 to partially block the opening 308, thereby resizing theoperational portion 312. The processor 250 then captures a further imagevia the image sensor 270 and repeats the detection. The processor 250 isthen configured to redefine the target positions 908 based on theoperational portion 312. Resizing the operational portion 312 thereforeallows the target positions 908 to be adjusted.

Referring to FIGS. 9A-9C, the processor 250 can, for example, beconfigured to adjust the location of the modification unit 216 from aninitial position, as shown in FIG. 9A in accordance with block 710 untiltwo label reference features 904-1 and 904-2 are at their targetpositions 908-1 and 908-2, as shown in FIG. 9B. The processor 250 canthen be configured to proceed to block 715 to move the cover 266 resizethe operational portion 312 to adjust the target positions 908-3 and908-4 to coincide with their respective label reference features 904-3and 904-4, as shown in FIG. 9C.

Returning to FIG. 7, at block 720, the processor 250 is configured toapply the selected removal mechanism. In the present example, theselected removal mechanism is laser erasing, hence the processor 250 isconfigured to control the laser 262 to emit a laser beam at the secondpower level to heat the rewriteable medium to the first thresholdtemperature to erase the content on the rewriteable medium. Theprocessor 250 is further configured to control the steering mechanism264 and the optical assembly 324 to control the shape of the laser beam(e.g. change the focus to create a larger spot) and steer the laser beamto portions of the rewriteable medium that need to be erased, asspecified by the label modification data. To ensure that the operationalportion 312 remains filled (i.e. that the apparatus 103 does not move,for example from being bumped) while the laser 262 is erasing the label804, the processor 250 can control the image sensor 270 to periodicallyor continuously capture images and process the captured images to verifythat the label reference features 904 are maintained at their targetpositions 908. If a label reference feature is not detected at itstarget position, the processor 250 is configured to disable the laser262.

In another example, the removal mechanism may be hot air, hence theprocessor 250 can be configured to control the hot air supply to emithot air into the conduit 316 for emission onto the rewriteable medium.The processor 250 can further control the cover 266 to the closedposition to protect components of the modification unit 216 disposed inthe cavity 304, and to utilize the cover 266 to diffuse airflow of thehot air across the rewriteable medium, for example by use of ridges or ahollow interior of the cover 266. In some examples, the processor 250can control the effector assembly 104 to move the modification unit 216and the conduit 316 across the rewriteable medium. The hot air isapplied to the rewriteable medium for a predetermined period of time, oruntil the temperature sensor 268 indicates that the hot air has reacheda predetermined temperature. For example, at a temperature of about 170°C., the hot air is expected to have heated the rewriteable medium to atemperature of about 130° C. to about 170° C. to erase the labelcontent.

At block 725, the processor 250 is configured to determine whether theerasing operation was successful. More particularly, the processor 250can be configured to control the cover 266 to the open position (e.g.when the cover 266 is in the closed position for a hot air erasingoperation) and to control the image sensor to capture one or moreimages. The captured images are processed to determine whether anycontent from the previous label 804 remains. When the determination atblock 725 is negative, the apparatus 103 is configured to repeat theperformance of block 720. When the determination at block 725 isaffirmative, the processor 250 is configured to proceed to block 730.

At block 730, the processor 250 is configured to then control the laser262 to emit a laser beam at the first power level to heat therewriteable medium to the first threshold temperature to write contenton the rewriteable medium. The processor 250 is further configured tocontrol the steering mechanism 264 to steer the laser beam to portionsof the rewriteable medium that need to be written. The steeringmechanism 264 may use for example vector movement (e.g. when the contentis defined by format statements, e.g. defining vertices, lines or thelike) or rasterization (e.g. when the content is defined by bit maps) tosteer the laser beam. As with erasing, to ensure that the operationalportion 312 remains filled (i.e. that the apparatus 103 does not move,for example from being bumped) while the laser 262 is writing content tothe rewriteable medium, the processor 250 can control the image sensor270 to periodically or continuously capture images and process thecaptured images to verify that the label reference features aremaintained at their target positions. The processor 250 can be furtherconfigured to disable the laser 262 if a label reference feature is notdetected at its target position.

Referring to FIG. 10A, an example image 1000 depicting a label 1004 isshown. In the present example, the label modification data can specify aprice update for the label 1004. The processor 250 is configured, in thepresent example, to select at block 705, the laser 262 as the selectedremoval mechanism based on the amount of modification required. Havinglocated the label 1004 and adjusted the location of the modificationunit 216, at block 720, the processor 250 can be configured to locatethe price portion, for example, by referencing the arrangement of labelcontent specified in the label modification data stored in therepository 120. The processor 250 can then control the laser 262, thesteering mechanism 264, and the optical assembly 324 to selectivelyerase the price portion. FIG. 10B depicts an example image 1008depicting the label 1004 having the price selectively erased. Havingselectively erased the price portion of the label 1004, the processor250 is configured to proceed to block 730. The processor 250 can controlthe laser 262, the steering mechanism 264, and the optical assembly 324to selectively write the new price portion on the label 1004. FIG. 10Cdepicts an example image 1012 depicting the label 1004 having the newprice written thereon.

As will now be apparent, when no previous label is detected at block 705(e.g. when no partial detection is registered after a threshold numberof incremental movements of the modification unit 216), the performanceof the method 700 can skip from block 705 directly to block 730. Inother examples, when the label modification data specifies only erasure,the method 700 can stop after block 725.

At block 735, the processor 250 is configured to determine whether thenew label was successfully written at block 730. For example, theprocessor 250 can be configured to retract the modification unit 216from the shelf edge 118 a and control the image sensor 270 to capture animage of the shelf edge 118 a. The captured image is processed todetermine whether all the content of the new label was successfullywritten. For example, the processor 250 may detect a barcode, a productidentifier and/or the price to verify the values match those specifiedin the label modification data. When the determination is affirmative,the apparatus 103 returns to block 435 of the method 400. When thedetermination is negative, the apparatus 103 is configured to repeatblock 720.

Variations to the above systems and methods are contemplated. Forexample, in some embodiments, the performance of block 410 of the method400 includes only placement of the modification unit 216 at an initiallocation, without navigating to a support structure. In suchembodiments, the apparatus 103 may lack a controllable locomotivemechanism, and may instead be moved to the support structure by anoperator. Following arrival at the support structure, the operator mayactivate an input on the apparatus 103 to initiate the performance ofblock 410 (that is, the control of the modification unit 216).

In the foregoing specification, specific embodiments have beendescribed. However, one of ordinary skill in the art appreciates thatvarious modifications and changes can be made without departing from thescope of the invention as set forth in the claims below. Accordingly,the specification and figures are to be regarded in an illustrativerather than a restrictive sense, and all such modifications are intendedto be included within the scope of present teachings.

The benefits, advantages, solutions to problems, and any element(s) thatmay cause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeatures or elements of any or all the claims. The invention is definedsolely by the appended claims including any amendments made during thependency of this application and all equivalents of those claims asissued.

Moreover in this document, relational terms such as first and second,top and bottom, and the like may be used solely to distinguish oneentity or action from another entity or action without necessarilyrequiring or implying any actual such relationship or order between suchentities or actions. The terms “comprises,” “comprising,” “has”,“having,” “includes”, “including,” “contains”, “containing” or any othervariation thereof, are intended to cover a non-exclusive inclusion, suchthat a process, method, article, or apparatus that comprises, has,includes, contains a list of elements does not include only thoseelements but may include other elements not expressly listed or inherentto such process, method, article, or apparatus. An element proceeded by“comprises . . . a”, “has . . . a”, “includes . . . a”, “contains . . .a” does not, without more constraints, preclude the existence ofadditional identical elements in the process, method, article, orapparatus that comprises, has, includes, contains the element. The terms“a” and “an” are defined as one or more unless explicitly statedotherwise herein. The terms “substantially”, “essentially”,“approximately”, “about” or any other version thereof, are defined asbeing close to as understood by one of ordinary skill in the art, and inone non-limiting embodiment the term is defined to be within 10%, inanother embodiment within 5%, in another embodiment within 1% and inanother embodiment within 0.5%. The term “coupled” as used herein isdefined as connected, although not necessarily directly and notnecessarily mechanically. A device or structure that is “configured” ina certain way is configured in at least that way, but may also beconfigured in ways that are not listed.

It will be appreciated that some embodiments may be comprised of one ormore generic or specialized processors (or “processing devices”) such asmicroprocessors, digital signal processors, customized processors andfield programmable gate arrays (FPGAs) and unique stored programinstructions (including both software and firmware) that control the oneor more processors to implement, in conjunction with certainnon-processor circuits, some, most, or all of the functions of themethod and/or apparatus described herein. Alternatively, some or allfunctions could be implemented by a state machine that has no storedprogram instructions, or in one or more application specific integratedcircuits (ASICs), in which each function or some combinations of certainof the functions are implemented as custom logic. Of course, acombination of the two approaches could be used.

Moreover, an embodiment can be implemented as a computer-readablestorage medium having computer readable code stored thereon forprogramming a computer (e.g., comprising a processor) to perform amethod as described and claimed herein. Examples of suchcomputer-readable storage mediums include, but are not limited to, ahard disk, a CD-ROM, an optical storage device, a magnetic storagedevice, a ROM (Read Only Memory), a PROM (Programmable Read OnlyMemory), an EPROM (Erasable Programmable Read Only Memory), an EEPROM(Electrically Erasable Programmable Read Only Memory) and a Flashmemory. Further, it is expected that one of ordinary skill,notwithstanding possibly significant effort and many design choicesmotivated by, for example, available time, current technology, andeconomic considerations, when guided by the concepts and principlesdisclosed herein will be readily capable of generating such softwareinstructions and programs and ICs with minimal experimentation.

The Abstract of the Disclosure is provided to allow the reader toquickly ascertain the nature of the technical disclosure. It issubmitted with the understanding that it will not be used to interpretor limit the scope or meaning of the claims. In addition, in theforegoing Detailed Description, it can be seen that various features aregrouped together in various embodiments for the purpose of streamliningthe disclosure. This method of disclosure is not to be interpreted asreflecting an intention that the claimed embodiments require morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive subject matter lies in less than allfeatures of a single disclosed embodiment. Thus the following claims arehereby incorporated into the Detailed Description, with each claimstanding on its own as a separately claimed subject matter.

1. An apparatus for labeling support structures, comprising: a chassishaving a locomotive assembly; an effector assembly having a first endcoupled to the chassis and a second end movable relative to the chassis;a label modification unit at the second end of the effector assembly,the label modification unit including an image sensor; and a controllercoupled to the locomotive assembly, the effector assembly and the labelmodification unit, the controller configured to: obtain labelmodification data defining a location relative to a reference feature ona support structure for a label modification operation; control thelocomotive assembly to travel to the support structure; detect thereference feature via image data captured at the image sensor; controlthe effector assembly to place the label modification unit at thelocation relative to the reference feature; and control the effectorassembly and the label modification unit to perform the labelmodification operation.
 2. The apparatus of claim 1, wherein theeffector assembly is a robotic arm.
 3. The apparatus of claim 2, furthercomprising a mast extending upwards from the chassis; wherein therobotic arm is supported at the first end on the mast.
 4. The apparatusof claim 1, wherein the label modification operation comprises at leastone of: (i) erasing previous label content from a rewriteable medium,and (ii) writing new label content to the rewriteable medium.
 5. Theapparatus of claim 4, wherein the label modification operation compriseswriting the new label content to the rewriteable medium responsive toerasing the previous label content from the rewriteable medium.
 6. Theapparatus of claim 4, further comprising a hot air supply configured tosupply hot air for application via an outlet of the label modificationunit; wherein the controller is configured to erase the previous labelcontent by controlling the hot air supply to apply the hot air to therewriteable medium.
 7. The apparatus of claim 4, wherein the labelmodification unit includes a laser configured to emit a laser beam in adirection towards the rewriteable medium; wherein the controller isconfigured to write the new label content by controlling the laser toheat the rewriteable medium to a first threshold temperature.
 8. Theapparatus of claim 7, wherein the controller is further configured toerase the previous label content by controlling the laser to heat therewriteable medium to a second threshold temperature.
 9. The apparatusof claim 7, wherein the label modification unit includes a housingconfigured to house the laser, the housing defining a cavity and anopening through which the laser beam is directed.
 10. The apparatus ofclaim 9, wherein the label modification unit further includes a coverconfigured to selectively block the opening.
 11. The apparatus of claim1, wherein the support structure includes a shelf module including alabel-bearing shelf edge; and wherein the reference feature is aboundary of the shelf module; and wherein the controller is configuredto detect the reference feature by: controlling the effector assembly toposition the label modification unit at an initial location relative tothe shelf module; capturing, via the image sensor, an image of the shelfmodule; and detecting the module boundary in the image.
 12. Theapparatus of claim 11, wherein the controller is further configured todetect the module boundary in the image by detecting a sequence ofgradient changes in the image.
 13. The apparatus of claim 8, wherein theprevious label content comprises a portion of content recorded on therewriteable medium.
 14. The apparatus of claim 10, further comprising ahot air supply configured to supply hot air for application via anoutlet of the label modification unit, the hot air supply including aheating element on a front side of the cover; and wherein the controlleris configured to erase the previous label content by controlling the hotair supply to heat the air via the heating element and apply the hot airto the rewriteable medium.
 15. A method of labeling support structures,comprising: at a controller of an apparatus: obtaining labelmodification data defining a location relative to a reference feature ona support structure for a label modification operation; controlling alocomotive assembly of the apparatus to travel to the support structure;detecting the reference feature in an image captured at an image sensorof the apparatus; controlling an effector assembly of the apparatus toplace the label modification unit at the location relative to thereference feature; and controlling the label modification unit toperform the label modification operation.
 16. The method of claim 15,wherein controlling the label modification unit to perform the labelmodification operation comprises controlling the label modification unitto at least one of (i) erase previous label content from a rewriteablemedium, and (ii) write new label content to the rewriteable medium. 17.The method of claim 16, wherein controlling the label modification unitto perform the label modification operation comprises controlling thelabel modification unit to write the new label content to therewriteable medium responsive to erasing the previous label content fromthe rewriteable medium.
 18. The method of claim 16, further comprisingcontrolling the label modification unit to erase the previous labelcontent by controlling a hot air supply to apply hot air to therewriteable medium via an outlet of the label modification unit.
 19. Themethod of claim 16, further comprising controlling the labelmodification unit to write new label content by controlling a laser toemit a laser beam to heat the rewriteable medium to a first thresholdtemperature.
 20. The method of claim 19, further comprising controllingthe label modification unit to erase the previous label content bycontrolling the laser to heat the rewriteable medium to a secondthreshold temperature.
 21. The method of claim 19, wherein the labelmodification unit includes a housing configured to house the laser, thehousing defining a cavity and an opening through which the laser beam isdirected.
 22. The method of claim 21, wherein the label modificationunit further comprises a cover configured to selectively block theopening.
 23. The method of claim 15, wherein the support structureincludes a shelf module including a label-bearing shelf edge; whereinthe reference feature is a boundary of the shelf module; and whereindetecting the reference feature comprises, at the controller:controlling the effector assembly to position the label modificationunit at an initial location relative to the shelf module; capturing, viathe image sensor, an image of the shelf module; and detecting the moduleboundary in the image.
 24. The method of claim 23, further comprising,at the controller, detecting the module boundary in the image bydetecting a sequence of gradient changes in the image.
 25. The method ofclaim 19, wherein the previous label content comprises a portion ofcontent recorded on the rewriteable medium.
 26. The method of claim 22,further comprising controlling the label modification unit to eraseprevious label content by controlling a hot air supply to heat air via aheating element on a front side of the cover and applying the hot air tothe rewriteable medium.